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<tr class="t-nv-h1"><td colspan="5"> 智能指针</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unique_ptr.html" title="cpp/memory/unique ptr"><span class="t-lines"><span>unique_ptr</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="default_delete.html" title="cpp/memory/default delete"><span class="t-lines"><span>default_delete</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> 分配器</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><strong class="selflink"><span class="t-lines"><span>allocator</span></span></strong></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator_traits.html" title="cpp/memory/allocator traits"><span class="t-lines"><span>allocator_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator_arg.html" title="cpp/memory/allocator arg"><span class="t-lines"><span>allocator_arg</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_construct_using_allocator.html" title="cpp/memory/uninitialized construct using allocator"><span class="t-lines"><span>uninitialized_construct_using_allocator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="scoped_allocator_adaptor.html" title="cpp/memory/scoped allocator adaptor"><span class="t-lines"><span>scoped_allocator_adaptor</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="polymorphic_allocator.html" title="cpp/memory/polymorphic allocator"><span class="t-lines"><span>pmr::polymorphic_allocator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> 内存资源</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="memory_resource.html" title="cpp/memory/memory resource"><span class="t-lines"><span>pmr::memory_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="get_default_resource.html" title="cpp/memory/get default resource"><span class="t-lines"><span>pmr::get_default_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="set_default_resource.html" title="cpp/memory/set default resource"><span class="t-lines"><span>pmr::set_default_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="new_delete_resource.html" title="cpp/memory/new delete resource"><span class="t-lines"><span>pmr::new_delete_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="null_memory_resource.html" title="cpp/memory/null memory resource"><span class="t-lines"><span>pmr::null_memory_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="synchronized_pool_resource.html" title="cpp/memory/synchronized pool resource"><span class="t-lines"><span>pmr::synchronized_pool_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="unsynchronized_pool_resource.html" title="cpp/memory/unsynchronized pool resource"><span class="t-lines"><span>pmr::unsynchronized_pool_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="monotonic_buffer_resource.html" title="cpp/memory/monotonic buffer resource"><span class="t-lines"><span>pmr::monotonic_buffer_resource</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="pool_options.html" title="cpp/memory/pool options"><span class="t-lines"><span>pmr::pool_options</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
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<tr class="t-nv-h1"><td colspan="5"> 未初始化存储</td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_copy.html" title="cpp/memory/uninitialized copy"><span class="t-lines"><span>uninitialized_copy</span></span></a></div></div></td></tr>
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<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_move.html" title="cpp/memory/uninitialized move"><span class="t-lines"><span>uninitialized_move</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_default_construct.html" title="cpp/memory/uninitialized default construct"><span class="t-lines"><span>uninitialized_default_construct</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_value_construct.html" title="cpp/memory/uninitialized value construct"><span class="t-lines"><span>uninitialized_value_construct</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="destroy.html" title="cpp/memory/destroy"><span class="t-lines"><span>destroy</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="destroy_at.html" title="cpp/memory/destroy at"><span class="t-lines"><span>destroy_at</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_copy_n.html" title="cpp/memory/uninitialized copy n"><span class="t-lines"><span>uninitialized_copy_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_fill_n.html" title="cpp/memory/uninitialized fill n"><span class="t-lines"><span>uninitialized_fill_n</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_move_n.html" title="cpp/memory/uninitialized move n"><span class="t-lines"><span>uninitialized_move_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_default_construct_n.html" title="cpp/memory/uninitialized default construct n"><span class="t-lines"><span>uninitialized_default_construct_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="uninitialized_value_construct_n.html" title="cpp/memory/uninitialized value construct n"><span class="t-lines"><span>uninitialized_value_construct_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="destroy_n.html" title="cpp/memory/destroy n"><span class="t-lines"><span>destroy_n</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="construct_at.html" title="cpp/memory/construct at"><span class="t-lines"><span>construct_at</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="raw_storage_iterator.html" title="cpp/memory/raw storage iterator"><span class="t-lines"><span>raw_storage_iterator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="get_temporary_buffer.html" title="cpp/memory/get temporary buffer"><span class="t-lines"><span>get_temporary_buffer</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="return_temporary_buffer.html" title="cpp/memory/return temporary buffer"><span class="t-lines"><span>return_temporary_buffer</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> 垃圾收集支持</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/declare_reachable.html" title="cpp/memory/gc/declare reachable"><span class="t-lines"><span>declare_reachable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/undeclare_reachable.html" title="cpp/memory/gc/undeclare reachable"><span class="t-lines"><span>undeclare_reachable</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/declare_no_pointers.html" title="cpp/memory/gc/declare no pointers"><span class="t-lines"><span>declare_no_pointers</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/undeclare_no_pointers.html" title="cpp/memory/gc/undeclare no pointers"><span class="t-lines"><span>undeclare_no_pointers</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/pointer_safety.html" title="cpp/memory/gc/pointer safety"><span class="t-lines"><span>pointer_safety</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="gc/get_pointer_safety.html" title="cpp/memory/gc/get pointer safety"><span class="t-lines"><span>get_pointer_safety</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> 杂项</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="pointer_traits.html" title="cpp/memory/pointer traits"><span class="t-lines"><span>pointer_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="to_address.html" title="cpp/memory/to address"><span class="t-lines"><span>to_address</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="addressof.html" title="cpp/memory/addressof"><span class="t-lines"><span>addressof</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="align.html" title="cpp/memory/align"><span class="t-lines"><span>align</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="assume_aligned.html" title="cpp/memory/assume aligned"><span class="t-lines"><span>assume_aligned</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> <a href="c.html" title="cpp/memory/c">C 库</a></td></tr>
<tr class="t-nv-col-table"><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/malloc.html" title="cpp/memory/c/malloc"><span class="t-lines"><span>malloc</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/aligned_alloc.html" title="cpp/memory/c/aligned alloc"><span class="t-lines"><span>aligned_alloc</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/calloc.html" title="cpp/memory/c/calloc"><span class="t-lines"><span>calloc</span></span></a></div></div></td></tr>
</table></div></td><td><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/realloc.html" title="cpp/memory/c/realloc"><span class="t-lines"><span>realloc</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="c/free.html" title="cpp/memory/c/free"><span class="t-lines"><span>free</span></span></a></div></div></td></tr>
</table></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> <a href="new.html" title="cpp/memory/new">低层内存管理</a></td></tr>
</table></div></td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><strong class="selflink"><tt>std::allocator</tt></strong><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv-h1"><td colspan="5"> 成员函数</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/allocator.html" title="cpp/memory/allocator/allocator"><span class="t-lines"><span>allocator::allocator</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/~allocator.html" title="cpp/memory/allocator/~allocator"><span class="t-lines"><span>allocator::~allocator</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/address.html" title="cpp/memory/allocator/address"><span class="t-lines"><span>allocator::address</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/allocate.html" title="cpp/memory/allocator/allocate"><span class="t-lines"><span>allocator::allocate</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/deallocate.html" title="cpp/memory/allocator/deallocate"><span class="t-lines"><span>allocator::deallocate</span></span></a></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/max_size.html" title="cpp/memory/allocator/max size"><span class="t-lines"><span>allocator::max_size</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/construct.html" title="cpp/memory/allocator/construct"><span class="t-lines"><span>allocator::construct</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/destroy.html" title="cpp/memory/allocator/destroy"><span class="t-lines"><span>allocator::destroy</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
<tr class="t-nv-h1"><td colspan="5"> 非成员函数</td></tr>
<tr class="t-nv"><td colspan="5"><div class="t-nv-ln-table"><div><a href="allocator/operator_cmp.html" title="cpp/memory/allocator/operator cmp"><span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div><div><span class="t-lines"><span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></span></span></div></div></td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<table class="t-dcl-begin"><tbody>
<tr class="t-dsc-header">
<td> <div>定义于头文件 <code><a href="../header/memory.html" title="cpp/header/memory">&lt;memory&gt;</a></code>
 </div></td>
<td></td>
<td></td>
</tr>
<tr class="t-dcl">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> T <span class="sy1">&gt;</span><br>
<span class="kw1">struct</span> allocator<span class="sy4">;</span></span></div></td>
<td> (1) </td>
<td class="t-dcl-nopad">  </td>
</tr>
<tr class="t-dcl t-until-cxx20">
<td> <div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;&gt;</span><br>
<span class="kw1">struct</span> allocator<span class="sy1">&lt;</span><span class="kw4">void</span><span class="sy1">&gt;</span><span class="sy4">;</span></span></div></td>
<td> (2) </td>
<td> <span class="t-mark">(C++17 中弃用)</span> <br><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span> </td>
</tr>
<tr class="t-dcl-sep"><td></td><td></td><td></td></tr>
</tbody></table>
<p><code>std::allocator</code> 类模板是所有标准库容器所用的默认<a href="../named_req/Allocator.html" title="cpp/named req/Allocator"><i>分配器</i> <span style="font-family: Georgia, 'DejaVu Serif', serif; font-style:italic">(Allocator)</span> </a>，若不提供用户指定的分配器。默认分配器无状态，即任何给定的 allocator 实例可交换、比较相等，且能解分配同一 allocator 类型的任何其他实例所分配的内存。
</p>
 <table class="t-rev-begin">
<tr class="t-rev t-until-cxx20"><td>
<p>对 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span></span></span> 的显式特化缺少成员 typedef <code>reference</code> 、 <code>const_reference</code> 、 <code>size_type</code> 和 <code>difference_type</code> 。此特化不声明成员函数。
</p>
</td>
<td><span class="t-mark-rev t-until-cxx20">(C++20 前)</span></td></tr>
<tr class="t-rev t-until-cxx11"><td> 所有自定义分配器必须也无状态。</td>
<td><span class="t-mark-rev t-until-cxx11">(C++11 前)</span></td></tr>
<tr class="t-rev t-since-cxx11"><td> 自定义分配器可以含有状态。每个容器或其他具分配器对象存储一个提供的分配器实例，并通过 <span class="t-lc"><a href="allocator_traits.html" title="cpp/memory/allocator traits">std::allocator_traits</a></span> 控制分配器替换。</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td></tr>
<tr class="t-rev t-since-cxx17"><td>
默认分配器满足<a href="../named_req/Allocator.html#.E5.88.86.E9.85.8D.E5.99.A8.E5.AE.8C.E6.95.B4.E6.80.A7.E8.A6.81.E6.B1.82" title="cpp/named req/Allocator">分配器完整性要求</a>。</td>
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td></tr>
</table>
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E7.B1.BB.E5.9E.8B">成员类型</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc-sep">
<td colspan="2">  
</td></tr>
<tr class="t-dsc-hitem">
<td>  类型
</td>
<td>  定义
</td></tr>


<tr class="t-dsc">
<td>  <code>value_type</code>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp">T</span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>pointer</code> <span class="t-mark">(C++17 中弃用)</span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp">T<span class="sy2">*</span></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>const_pointer</code> <span class="t-mark">(C++17 中弃用)</span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">const</span> T<span class="sy2">*</span></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>reference</code> <span class="t-mark">(C++17 中弃用)</span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp">T<span class="sy3">&amp;</span></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>const_reference</code> <span class="t-mark">(C++17 中弃用)</span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">const</span> T<span class="sy3">&amp;</span></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>size_type</code>
</td>
<td>  <span class="t-lc"><a href="../types/size_t.html" title="cpp/types/size t">std::size_t</a></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>difference_type</code>
</td>
<td>  <span class="t-lc"><a href="../types/ptrdiff_t.html" title="cpp/types/ptrdiff t">std::ptrdiff_t</a></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>propagate_on_container_move_assignment</code><span class="t-mark-rev t-since-cxx14">(C++14)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../types/integral_constant.html"><span class="kw649">std::<span class="me2">true_type</span></span></a></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>rebind</code> <span class="t-mark">(C++17 中弃用)</span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> U <span class="sy1">&gt;</span> <span class="kw1">struct</span> rebind <span class="br0">{</span> <span class="kw1">typedef</span> allocator<span class="sy1">&lt;</span>U<span class="sy1">&gt;</span> other<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span></span></span>
</td></tr>

<tr class="t-dsc">
<td>  <code>is_always_equal</code><span class="t-mark-rev t-since-cxx17">(C++17)</span>
</td>
<td>  <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="../types/integral_constant.html"><span class="kw649">std::<span class="me2">true_type</span></span></a></span></span>
</td></tr>
</table>
<h3><span class="mw-headline" id=".E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">成员函数</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="allocator/allocator.html" title="cpp/memory/allocator/allocator"> <span class="t-lines"><span>(构造函数)</span></span></a></div></div>
</td>
<td>  创建新的 allocator 实例 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div t-dsc-member-nobold-div"><div><a href="allocator/~allocator.html" title="cpp/memory/allocator/~allocator"> <span class="t-lines"><span>(析构函数)</span></span></a></div></div>
</td>
<td>  析构 allocator 实例 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/address.html" title="cpp/memory/allocator/address"> <span class="t-lines"><span>address</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-deprecated-cxx17">(C++17 中弃用)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span></span></div></div>
</td>
<td>  获得对象的地址，即使重载了 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy3">&amp;</span></span></span> <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/allocate.html" title="cpp/memory/allocator/allocate"> <span class="t-lines"><span>allocate</span></span></a></div></div>
</td>
<td>  分配未初始化的存储 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/deallocate.html" title="cpp/memory/allocator/deallocate"> <span class="t-lines"><span>deallocate</span></span></a></div></div>
</td>
<td>  解分配存储 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/max_size.html" title="cpp/memory/allocator/max size"> <span class="t-lines"><span>max_size</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-deprecated-cxx17">(C++17 中弃用)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span></span></div></div>
</td>
<td>  返回最大的受支持分配大小 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/construct.html" title="cpp/memory/allocator/construct"> <span class="t-lines"><span>construct</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-deprecated-cxx17">(C++17 中弃用)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span></span></div></div>
</td>
<td>  在分配的存储构造对象 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/destroy.html" title="cpp/memory/allocator/destroy"> <span class="t-lines"><span>destroy</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-deprecated-cxx17">(C++17 中弃用)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span></span></div></div>
</td>
<td>  析构在已分配存储中的对象 <br> <span class="t-mark">(公开成员函数)</span> </td></tr>
</table>
<h3><span class="mw-headline" id=".E9.9D.9E.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">非成员函数</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator/operator_cmp.html" title="cpp/memory/allocator/operator cmp"> <span class="t-lines"><span>operator==</span><span>operator!=</span></span></a></div><div><span class="t-lines"><span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span></span></div></div>
</td>
<td>  比较两个分配器实例  <br> <span class="t-mark">(公开成员函数)</span> </td></tr>
</table>
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
<p>成员模板 <code>rebind</code> 提供获得不同类型的 allocator 的方式。例如，
</p>
 <table class="t-rev-begin">
<tr class="t-rev t-until-cxx11"><td> <code>std::list&lt;T, A&gt;</code> 用分配器 <span class="t-c"><span class="mw-geshi cpp source-cpp">A<span class="sy4">::</span><span class="me2">rebind</span><span class="sy1">&lt;</span>Node<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">::</span><span class="me2">other</span></span></span> 分配某个内部类型 <code>Node&lt;T&gt;</code> 结点  
</td>
<td><span class="t-mark-rev t-until-cxx11">(C++11 前)</span></td></tr>
<tr class="t-rev t-since-cxx11"><td> <code>std::list&lt;T, A&gt;</code> 用分配器 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="allocator_traits.html"><span class="kw700">std::<span class="me2">allocator_traits</span></span></a><span class="sy1">&lt;</span>A<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">rebind_alloc</span><span class="sy1">&lt;</span>Node<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span></span></span> 分配某个内部类型 <code>Node&lt;T&gt;</code> 结点，这用 <span class="t-c"><span class="mw-geshi cpp source-cpp">A<span class="sy4">::</span><span class="me2">rebind</span><span class="sy1">&lt;</span>Node<span class="sy1">&lt;</span>T<span class="sy1">&gt;&gt;</span><span class="sy4">::</span><span class="me2">other</span></span></span> 实现，若 A 是 <code>std::allocator</code> 
</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td></tr>
</table>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
<div class="t-example"><div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">运行此代码</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;memory&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    std<span class="sy4">::</span><span class="me2">allocator</span><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy1">&gt;</span> a1<span class="sy4">;</span>   <span class="co1">// int 的默认分配器</span>
    <span class="kw4">int</span><span class="sy2">*</span> a <span class="sy1">=</span> a1.<span class="me1">allocate</span><span class="br0">(</span><span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>  <span class="co1">// 一个 int 的空间</span>
    a1.<span class="me1">construct</span><span class="br0">(</span>a, <span class="nu0">7</span><span class="br0">)</span><span class="sy4">;</span>       <span class="co1">// 构造 int</span>
    <a href="../io/cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> a<span class="br0">[</span><span class="nu0">0</span><span class="br0">]</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
    a1.<span class="me1">deallocate</span><span class="br0">(</span>a, <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>      <span class="co1">// 解分配一个 int 的空间</span>
 
    <span class="co1">// string 的默认分配器</span>
    std<span class="sy4">::</span><span class="me2">allocator</span><span class="sy1">&lt;</span><a href="../string/basic_string.html"><span class="kw1229">std::<span class="me2">string</span></span></a><span class="sy1">&gt;</span> a2<span class="sy4">;</span>
 
    <span class="co1">// 同上，但以 a1 的重绑定获取</span>
    decltype<span class="br0">(</span>a1<span class="br0">)</span><span class="sy4">::</span><span class="me2">rebind</span><span class="sy1">&lt;</span><a href="../string/basic_string.html"><span class="kw1229">std::<span class="me2">string</span></span></a><span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">other</span> a2_1<span class="sy4">;</span>
 
    <span class="co1">// 同上，但通过 allocator_traits 由类型 a1 的重绑定获取</span>
    <a href="allocator_traits.html"><span class="kw700">std::<span class="me2">allocator_traits</span></span></a><span class="sy1">&lt;</span>decltype<span class="br0">(</span>a1<span class="br0">)</span><span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">rebind_alloc</span><span class="sy1">&lt;</span><a href="../string/basic_string.html"><span class="kw1229">std::<span class="me2">string</span></span></a><span class="sy1">&gt;</span> a2_2<span class="sy4">;</span>
 
    <a href="../string/basic_string.html"><span class="kw1229">std::<span class="me2">string</span></span></a><span class="sy2">*</span> s <span class="sy1">=</span> a2.<span class="me1">allocate</span><span class="br0">(</span><span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 2 个 string 的空间</span>
 
    a2.<span class="me1">construct</span><span class="br0">(</span>s, <span class="st0">"foo"</span><span class="br0">)</span><span class="sy4">;</span>
    a2.<span class="me1">construct</span><span class="br0">(</span>s <span class="sy2">+</span> <span class="nu0">1</span>, <span class="st0">"bar"</span><span class="br0">)</span><span class="sy4">;</span>
 
    <a href="../io/cout.html"><span class="kw1757">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> s<span class="br0">[</span><span class="nu0">0</span><span class="br0">]</span> <span class="sy1">&lt;&lt;</span> <span class="st0">' '</span> <span class="sy1">&lt;&lt;</span> s<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
    a2.<span class="me1">destroy</span><span class="br0">(</span>s<span class="br0">)</span><span class="sy4">;</span>
    a2.<span class="me1">destroy</span><span class="br0">(</span>s <span class="sy2">+</span> <span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
    a2.<span class="me1">deallocate</span><span class="br0">(</span>s, <span class="nu0">2</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div></div>
<p>输出：
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">7
foo bar</pre></div></div> 
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
<table class="t-dsc-begin">

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="allocator_traits.html" title="cpp/memory/allocator traits"> <span class="t-lines"><span>allocator_traits</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   提供关于分配器类型的信息  <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="scoped_allocator_adaptor.html" title="cpp/memory/scoped allocator adaptor"> <span class="t-lines"><span>scoped_allocator_adaptor</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   为多级容器实现的多级分配器  <br> <span class="t-mark">(类模板)</span> </td></tr>

<tr class="t-dsc">
<td>  <div class="t-dsc-member-div"><div><a href="uses_allocator.html" title="cpp/memory/uses allocator"> <span class="t-lines"><span>uses_allocator</span></span></a></div><div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx11">(C++11)</span></span></span></div></div>
</td>
<td>   检查指定的类型是否支持使用分配器的构造  <br> <span class="t-mark">(类模板)</span> </td></tr>
</table>

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